Proposed hypothesis is based on the interplay between two force components acting on the rotating coil. The tangential force component generates the Archimedean screw effect to move two solvent phases toward the head of the coil whereas the radial force component acts against the Archimedean screw force to establish hydrostatic distribution of the two phases throughout the coil. The unilateral hydrodynamic distribution of the two phases is governed by the degree of asymmetry in the radial force field on the coil in both simple rotation and synchronous planetary motion. The present hypothesis successfully explains all the observed hydrodynamic phenomena reported in the past.